Local anesthetic agents are used to anesthetize peripheral nerves during many surgical procedures, such as for example during dental surgery. However, profound anesthesia is not always achieved and patients may experience pain during surgical manipulation of the tissue innervated by the incompletely anesthetized nerve. For example, success rates of from only 21% to 67% have been reported when local anesthetic agents have been used to block the inferior alveolar nerve, i.e., the primary nerve of the lower jaw, and its terminal branches. If the area undergoing surgical manipulation is inflamed or if the patient presents with pain, the success rate for profound anesthesia using current techniques and anesthetic compositions is even less.
In recent years studies have been conducted to determine whether increasing the concentration of the local anesthetic agent in the anesthetic composition, increasing the volume of the anesthetic composition administered to the target site, or adding sodium bicarbonate, hyaluronidase, or benadryl to conventional local anesthetic compositions increases the success rate of local anesthesia in the mouth region. Unfortunately, none of these modifications had a significant effect on the anesthetic success rate.
Accordingly, it is desirable to have new anesthetic compositions which are more effective at inhibiting the excitation-conduction process of peripheral nerves, particularly the peripheral nerves the mouth region. New and improved methods for anesthetizing the peripheral nerves of the mouth region are also desirable.